During respiration, the anatomy, shape, tissue composition and properties of the human airway produce airflow resistance. The nose is responsible for almost two thirds of this resistance. Most of the resistance occurs in the anterior part of the nose, known as the internal nasal valve, which acts as a flow-limiter. Although this flow-limiting effect of the internal nasal valve works well in most people, a large number of people have a poorly functioning nasal valve, which results in too much resistance to breathing and thus respiration abnormalities, which can significantly affect a patient's quality of life.
The internal nasal valve area is formed by the nasal septum, the caudal border of the upper lateral cartilage (ULC), the head of the inferior turbinate, and the pyriform aperture and tissues that surround it. The angle formed between the caudal border of the ULC and the nasal septum is normally about 10-15 degrees, as illustrated in FIG. 2A. The internal nasal valve is usually the narrowest part of the nasal airway and is responsible for more than two thirds of the airflow resistance produced by the nose. Inadequate nasal valve structural strength, stiffness or conformation can be a consequence of previous surgery, trauma, aging, and/or primary weakness of the upper lateral cartilage.
Poor nasal airflow can also occur in people with a structurally normal nasal/nasal valve anatomy, as well as a normal nasal passage cross-sectional area. The strength, structure and resistance to collapse of the nasal passage can also be normal in people with poor nasal airflow. People can have poor nasal airflow from other causes, including deviated septum, allergic rhinitis (runny nose), non-allergic rhinitis, turbinate hyperplasia, nasal tip ptosis, and nasal polyposis (nasal polyps). Regardless of the cause, poor nasal breathing and/or nasal congestion has profound effects on a person's health and quality of life.
Existing methods for correcting nasal valve inadequacy include surgically repositioning the upper lateral cartilage or adding structural grafts to support the lateral wall of the nose. Surgical structural enhancement of the valve can include the use of grafts made from cartilage or any of a number of other materials. The most frequent methods involve surgical implantation of spreader grafts between the upper lateral cartilage and the nasal septum. Alternately, stents, spreaders or other devices may be implanted to reposition the ULC. Although they work in some cases, invasive surgical and implant solutions may also involve substantial risk and post-surgical discomfort.
Another attempted solution to nasal valve insufficiency involves the use of external (non-implanted) nasal dilators, placed temporarily and removed by the patient. Such external devices, such as the “Breathe Right” strip, are placed on the outside surface of the nose. Example of such devices are described in U.S. Pat. Nos. 5,533,499 and 7,114,495. Other devices may be temporarily placed in the nasal cavity but not surgically implanted, for example the devices described in U.S. Pat. Nos. 7,055,523 and 6,978,781. These temporary devices, whether external or internal, can be uncomfortable, unsightly, cause skin irritation, and require frequent removal and replacement by the patient.
The assignee of the present application has developed devices, systems and methods for treating the upper airway to ameliorate nasal valve insufficiency, runny nose and/or other conditions. Further description of these devices, systems and methods may be found, for example, in the patents and applications incorporated by reference above. Despite the many advances described in those and other references, improvements and enhancements are still desirable.